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Thursday, 3 November 2016

Sea Ice Loss as Start of Arctic De-Wintering

Drifting
into Arctic Un-Winter

Many
call it global weirding. But weird just barely describes what’s
happening in the Arctic right now. To the consternation of some, I’ve
warned that the process we are now witnessing is the start to a kind
of death of winter that
will assuredly happen if we don’t stop burning fossil fuels soon.
But we could just as well call it un-winter. Or de-wintering.
Whatever you want to name it, and regardless of whether your initial
inclination is to downplay it or to shout it from the hills, what’s
happening in the Arctic right now is unprecedented and more than a
little scary.

Sea
Ice Loss as Start of Arctic De-Wintering

The
Arctic Ocean has lost a great deal of its ice coverage during summer
over recent years. Darker oceans reflect less of the sun’s rays.
And more heat gets transferred to the water’s surface. As summer
transitions into fall, this added energy loading creates a latent
heat barrier to ice refreeze. Without its traditional ice coverage,
the ocean then ventilates this heat into the Arctic environment —
keeping air temperatures abnormally warm, increasing water vapor
content, and thickening the Arctic atmosphere.

(Temperature
departures for the entire Arctic have exceeded 6 C above average for
three out of the past four days. The delay of the usual fall
progression of cooling toward winter is a month or more behind
schedule for this region of our world. Image source: Climate
Reanalyzer.)

Today,
the temperature above the Arctic Circle is averaging 6.21 degrees
Celsius above average. Large local areas are seeing temperatures in
the range of 15 to 20 degrees Celsius above average with locally
higher peaks. Beyond the 80 degree north latitudeline,temperatures
are currently about 12 degrees Celsius above average.
The result is that most places in the Arctic are about 25 to 40 days
behind the average cooling trend line and that temperatures are more
reminiscent of late September or early October than early November.

Sea
Ice Record Lows Are Likewise Extreme

Not
only is the added ocean heat pumping season-wrenching warmth into the
Arctic atmosphere, it is also generating a self-reinforcing feedback
loop with record low sea ice departures that have been worsening with
each passing day. According to JAXA, current Arctic Ocean sea ice
extents are now 710,000 square kilometers below the previous record
low set in 2012. That’s an area larger than the state of Texas. But
when you compare this new record low to averages seen in the 1980s, a
region the size of Texas, Alaska, and California combined have been
lost.

(Arctic
sea ice extents of 7.03 million square kilometers on November 1 of
2016 are about equal to end summer sea ice minimums during the 1990s.
So much open ocean is having a dramatic warming effect on the Arctic
atmosphere during the Fall of 2016. Image source:JAXA.)

All
that naked ocean dumping heat into the atmosphere is having a marked
effect. One that is producing these extreme temperatures even as it
generates a self-sustaining cycle that prevents refreeze.

How
long this vicious tug of war will continue to last is anyone’s
guess. It ultimately boils down to how much heat the Arctic Ocean has
taken in and how much energy is still being transferred in that
direction. With La Nina forming in the Pacific, ocean and atmospheric
heat transfer toward the Arctic would tend to ramp up. And we may
well be seeing a kind of teleconnection type handshake between polar
amplification and the ENSO cycle now.

To
this point it’s worth noting that the most recent big heat pulse in
the Arctic started with the powerful 2015-2016 El Nino. And this
traditional natural variability related heat transfer is likely to
continue to push the scales for Arctic heat content through 2017 and
possibly into 2018. The question in this case is whether or not
climate change related warming is being enabled by this periodic flux
to hit a new tipping point. And from the perspective of this fall,
things don’t look very good for the Arctic.